Radiographic imaging such as x-ray imaging has been used for years in medical applications and for non-destructive testing.
Normally, an x-ray imaging system includes an x-ray source and an x-ray detector consisting of multiple detector elements. The x-ray source emits x-rays, which pass through a subject or object to be imaged and are then registered by the detector. Since some materials absorb a larger fraction of the x-rays than others, an image is formed of the subject or object.
In the electronic read out chain of a direct conversion energy-sensitive multi-bin detector, the interacting x-ray quantum generates a voltage pulse the height of which is proportional to the energy deposited in the sensor by the incident x-ray quantum. This height is compared in a multitude of comparators with tunable voltage settings. These comparator settings are often denoted thresholds and the voltage span between adjacent thresholds defines a so-called bin. When an x-ray deposits energy that results in a voltage pulse falling within a certain bin, a corresponding counter is incremented and this is how energy information is extracted in a photon-counting multi-bin detector.
However, x-ray imaging systems based on photon-counting multi-bin detectors still suffer from artifacts in the reconstructed image and also make material basis decomposition of the spectral data difficult.
There is thus a general demand to improve radiographic imaging such as x-ray imaging.